Over the past years a desire for smaller electronic form factors and power consumption along with increased performance has driven an integration of device components. One area where integration took place is area of MEMS devices. More specifically, microphones in electronic devices such as, e.g., cell phones, laptops, and tablets are predominately MEMS microphones.
A feature in the performance of a MEMS microphone is the size of the back volume. The back volume provides a reference pressure against incident sound waves. Typically, the back volume is defined by the substrate of the silicon microphone.